Existing CoAP primarily focuses on communication (i.e., client/server-based request/response interaction) between constrained devices in a constrained network. Constrained networks may have large latencies and constrained devices may not be able to respond in a timely manner. Therefore, incorporating delay awareness in the CoAP protocol may prove beneficial for communications between devices. This article presents a new method to support a delay-aware CoAP messaging model, where a Delay- Indicator is proposed to be contained in messages to reflect delay tolerance information. Furthermore, the Delay-Indicator can be leveraged by CoAP Clients and CoAP Servers to improve their operations of entering sleep mode to save energy while not violating delay tolerances. With this new enabler, a timeout mechanism for CoAP Responses is put forward to enhance CoAP performance. Simulation results show that incorporating delay awareness in CoAP significantly improves messaging performance.

中文翻译：

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物联网延迟感知应用协议


现有的CoAP主要关注受限网络中受限设备之间的通信（即，基于客户端/服务器的请求/响应交互）。受限网络可能会有较大的延迟，受限设备可能无法及时响应。因此，在 CoAP 协议中加入延迟感知可能有利于设备之间的通信。本文提出了一种支持延迟感知 CoAP 消息传递模型的新方法，其中建议在消息中包含延迟指示符以反映延迟容忍信息。此外，CoAP 客户端和 CoAP 服务器可以利用延迟指示器来改进其进入睡眠模式的操作，以节省能源，同时不违反延迟容限。借助这个新的使能器，提出了 CoAP 响应的超时机制以增强 CoAP 性能。仿真结果表明，在 CoAP 中加入延迟感知可显着提高消息传递性能。